Abstract: Oil transporting, pipelines in our country suffer from the ageing of corrosion protection layer and the corrosion of pipe steel with the increase of service time. In order to en-sure safety operafian it must be done for corrosion protection layers of pipelines to repair or to renovate, The damage conditions and cause analysis are introduced in the paper, the probleme existing in overhaul and three points of requirement for overhaul are also stated.